This study is designed to develop essential normative data on new audiologic tests, equipment and applications. These procedures and instruments are important to the work of the audiology program in facilitating our ability to provide new insights into auditory system function in various disease states or therapeutic regimens. In addition, these new norms permit more effective collaboration with physicians and other researches studying these special populations. These specific data do not exist in the literature for some age groups and many special auditory test procedures. The data are essential for using these new techniques as clinical tools in differential assessment of auditory function.